1. Technical Field
The present invention relates to a fluid transporter which delivers a small quantity of fluid at a low speed, and a method for driving this fluid transporter.
2. Related Art
A peristaltic pump is known as a device for transporting liquid at a low speed. Examples of the peristaltic pump include a type which sequentially presses an elastic tube as a fluid transportation channel from the upstream side to the downstream side by using a plurality of fingers operated in accordance with the drive of a cam unit such that liquid can be pushed out of the tube for delivery therefrom by the press of the plural fingers against the tube for closure of the tube (for example, see JP-T-2001-515557).
According to the pump which delivers fluid by the press of the plural fingers against the tube for closure thereof as in the disclosure of JP-T-2001-515557, the rotation angle of the cam unit and the delivery amount exhibit a non-linear relationship. Therefore, errors are produced in the delivery amount when the delivery amount is controlled only by the rotation angle, which makes it difficult to control the delivery amount with high accuracy. However, particularly in case of injection of a liquid medicine into a living body, accurate control over the delivery amount is required.
Moreover, when the cam unit is started from an arbitrary rotation position at the time of priming (initial injection of liquid medicine), an accurate delivery amount of the liquid medicine is difficult to be provided.
Furthermore, the inside diameter of the elastic tube (diameter of fluid flow section) has manufacturing variations. Thus, even under the same driving condition, the delivery amount may be varied according to the variations of the inside diameter of the tube.